ConverterBMI Calculator: What the Result Means and Does Not Mean
Interpret a metric BMI value using explicitly selected CDC adult categories while keeping screening, age, and body-composition limits visible.
Need To Check A Conversion?
Use the BMI Calculator tool for the direct action. This guide stays focused on the explanation, tradeoffs, mistakes, and reference context behind that task.
BMI Is A Screening Value
Body mass index relates weight to height. The metric formula is weight in kilograms divided by height in meters squared.
BMI does not directly measure body fat and cannot distinguish fat mass from muscle or bone. It is one screening indicator, not a diagnosis or a complete assessment of health risk.
CDC Adult Categories For Age 20 Or Older
| Unrounded BMI | CDC category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to below 25 | Healthy Weight |
| 25 to below 30 | Overweight |
| 30 to below 35 | Obesity, class 1 |
| 35 to below 40 | Obesity, class 2 |
| 40 or higher | Obesity, class 3 |
Raw Classification And Display Rounding
The category is selected from the unrounded BMI. The visible value is then formatted to one decimal place, so a boundary-adjacent display can look like the next threshold even though the raw value remains just below it.
For ages 2 through 19, CDC uses sex-specific BMI-for-age percentiles instead of the adult cutoffs. This tool therefore requires the adult category context to be selected explicitly.
Interpretation Limits
- Do not use BMI as a direct body-fat measurement.
- Do not apply the adult table to children or teenagers.
- Consider medical history and other measurements when health interpretation matters.
- Keep the original height and weight with a saved result.
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References
- CDC Adult BMI Categories - Primary U.S. public-health source for adult age scope, category labels, thresholds, and obesity classes.
- CDC BMI Frequently Asked Questions - Primary source for formula context and screening limitations.
- CDC Child And Teen BMI Categories - Primary source for age- and sex-specific interpretation from ages 2 through 19.
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